When used appropriately, combinations of newly available, highly active antiviral therapies (HAART) can lead to prolonged suppression of detectable HIV replication. Maintenance of undetectable viremia is associated with interruptions of HIV-induced immunodeficiency and with the prevention of emergence of reisistant HIV variants. However, even after two years of HAART, HIV can still be cultured from certain cell populations. Because eradication of HIV from an individual is not yet possible, the goal of therapy is to block virus replication and to prevent immunologic damage for the lifetime of an infected individual.